/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.confignode.manager.node.heartbeat;

import org.apache.iotdb.commons.cluster.NodeStatus;
import org.apache.iotdb.confignode.conf.ConfigNodeDescriptor;

public class ConfigNodeHeartbeatCache extends BaseNodeCache {

    /**
     * Only get CURRENT_NODE_ID here due to initialization order
     */
    public static final int CURRENT_NODE_ID =
            ConfigNodeDescriptor.getInstance().getConf().getConfigNodeId();

    public static final NodeStatistics CURRENT_NODE_STATISTICS =
            new NodeStatistics(0, NodeStatus.Running, null);

    private final int configNodeId;

    /**
     * Constructor for create ConfigNodeHeartbeatCache with default NodeStatistics
     */
    public ConfigNodeHeartbeatCache(int configNodeId) {
        super();
        this.configNodeId = configNodeId;
    }

    /**
     * Constructor only for ConfigNode-leader
     */
    public ConfigNodeHeartbeatCache(int configNodeId, NodeStatistics statistics) {
        super();
        this.configNodeId = configNodeId;
        this.previousStatistics = statistics;
        this.currentStatistics = statistics;
    }

    @Override
    protected void updateCurrentStatistics() {
        // Skip itself
        if (configNodeId == CURRENT_NODE_ID) {
            return;
        }

        long lastSendTime = 0;
        synchronized (slidingWindow) {
            if (!slidingWindow.isEmpty()) {
                lastSendTime = slidingWindow.getLast().getSendTimestamp();
            }
        }

        // Update Node status
        NodeStatus status;
        // TODO: Optimize judge logic
        if (System.currentTimeMillis() - lastSendTime > HEARTBEAT_TIMEOUT_TIME) {
            status = NodeStatus.Unknown;
        } else {
            status = NodeStatus.Running;
        }

        /* Update loadScore */
        // Only consider Running ConfigNode as available currently
        // TODO: Construct load score module
        long loadScore = NodeStatus.isNormalStatus(status) ? 0 : Long.MAX_VALUE;

        NodeStatistics newStatistics = new NodeStatistics(loadScore, status, null);
        if (!currentStatistics.equals(newStatistics)) {
            // Update the current NodeStatistics if necessary
            currentStatistics = newStatistics;
        }
    }
}
